Quantum mechanics is based on two formulae. The first is Schroedinger’s Equation, aka “the wave equation”. It’s about a hundred years old and is stupendously useful. Physicists use it to calculate just about everything we want to know about the subatomic world. Schroedinger’s Equation does for the subatomic world what Newton’s laws did for the macroscopic world. You can use Newton’s laws to plan a rocket’s journey to Saturn and it will get almost exactly where you aimed it. Schroedinger’s Law does the same thing for atoms, nuclei, and subatomic particles. Because of its immense computational power, physicists generally regard Schroedinger’s Equation as the heart and soul of quantum mechanics.
I have never shared that perception. For me, Schroedinger’s Equation is not “deep physics” because it really doesn’t explain anything at a deep, fundamental level. It’s more of an engineering equation. For me, the essence of quantum mechanics has always been Heisenberg’s Uncertainty Principle. It’s useless for computing electron clouds around atoms or the behavior of nucleons, or any of the many other phenomena that Schroedinger’s Equation calculates. But it gets closer to the essence of what’s going on in quantum mechanics than anything else.
Here’s my wild, crazy hypothesis that I’m sure will lead you to conclude that I have become senile: time isn’t a fundamental component of the universe. It is a consequence of deeper principles, not a fundamental cause of anything. I can offer a number of arguments to support this claim, but I’ll keep this essay short and provide additional arguments in subsidiary essays.
One of Einstein’s most important contributions to physics is seldom heralded. In his theory of general relativity, he pointed out that we measure the gridwork of space using light. If you want to line up a bunch of tables in a hall, you make your first attempt, then stand at the end of the line of tables and look right down the line to see if they are all in line:
Looking down this line, you can readily see that the second table is out of line. But here’s the catch: you determine the straightness of the line with light. You line up your eye with what you think is the end of the line and look down that line to see if everything is right. In other words, we use light to determine the architecture of space.
Einstein took this to the next step: he pointed out that, since light defines the straightness of space, then since gravity bends the path of a ray of light, gravity is actually bending space itself. This led to notions of the curvature of space and all sorts of relativistic strangeness.
The conclusion we abstract from this observation is that the measurement defines the reality. Space is what we observe it to be, not some mathematical abstraction. We can apply this principle to time with surprising results. We measure time with a clock, right? But how does a clock work? An old-time clock has a spring that powers the movement of the hands.
From EduSphere Academy
As the clock ticks, the spring unwinds, generating entropy. It doesn’t matter whether the clock is an old-time mechanical clock or an electric clock or even an atomic clock in a laboratory; the process of measuring time always results in the generation of entropy.
This brings us to the Second Law of Thermodynamics, which states that the entropy of an isolated system (one that is not stealing negentropy from somewhere else) must never decrease with time. In fact, the entropy of almost all systems almost always increases with time.
We could rephrase the general idea of the Second Law as follows:
“As time increases, entropy increases.”
But note that we can reverse the statement to get:
“As entropy increases, time increases.”
That is, both are increasing together, so which is the cause and which is the effect? We have always thought of time as the causal factor, but we have no proof of that; we’ve just assumed it. For all we know, the causality flows in the opposite direction.
That will surely strike you as a peculiar way of thinking. After all, the ticking of the watch doesn’t MAKE time go forward; it simply echoes the inevitable advance of time. Right?
Here’s where that line of thinking goes wrong: it’s not the watch that drives time. It’s not any single process that drives time forward. It’s every process in the universe that’s driving time forward. The universe is itself an isolated system; its entropy must increase with time. Or, as I would put it, the natural increase in entropy is what drives time.
You’re probably still suspicious of this idea, so let me put it in a more personal way. Consider how you perceive the passage of time. There are neurons in your brain that are firing away, expending energy to drive the mental processes that constitute your perception of time. Those neurons are increasing your entropy by expending energy. In other words, you cannot perceive time without increasing entropy. It is the increase of entropy that permits you to perceive time.